Commit 0a53c9ac authored by Peter Zijlstra's avatar Peter Zijlstra
Browse files

x86/xen: Make read_cr2() noinstr 



vmlinux.o: warning: objtool: pv_ops[41]: native_read_cr2
vmlinux.o: warning: objtool: pv_ops[41]: xen_read_cr2
vmlinux.o: warning: objtool: pv_ops[41]: xen_read_cr2_direct
vmlinux.o: warning: objtool: exc_double_fault()+0x15: call to pv_ops[41]() leaves .noinstr.text section

Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: default avatarJuergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20210624095148.500331616@infradead.org
parent eac46b32

arch/x86/include/asm/paravirt.h

+1 −1
Original line number Diff line number Diff line
@@ -133,7 +133,7 @@ static inline void write_cr0(unsigned long x) 
	PVOP_VCALL1(cpu.write_cr0, x);

}



static inline unsigned long read_cr2(void)

static __always_inline unsigned long read_cr2(void)

{

	return PVOP_ALT_CALLEE0(unsigned long, mmu.read_cr2,

				"mov %%cr2, %%rax;",

arch/x86/kernel/paravirt.c

+6 −1
Original line number Diff line number Diff line
@@ -218,6 +218,11 @@ void paravirt_end_context_switch(struct task_struct *next) 
	if (test_and_clear_ti_thread_flag(task_thread_info(next), TIF_LAZY_MMU_UPDATES))

		arch_enter_lazy_mmu_mode();

}



static noinstr unsigned long pv_native_read_cr2(void)

{

	return native_read_cr2();

}

#endif



enum paravirt_lazy_mode paravirt_get_lazy_mode(void)
@@ -298,7 +303,7 @@ struct paravirt_patch_template pv_ops = { 
	.mmu.exit_mmap		= paravirt_nop,



#ifdef CONFIG_PARAVIRT_XXL

	.mmu.read_cr2		= __PV_IS_CALLEE_SAVE(native_read_cr2),

	.mmu.read_cr2		= __PV_IS_CALLEE_SAVE(pv_native_read_cr2),

	.mmu.write_cr2		= native_write_cr2,

	.mmu.read_cr3		= __native_read_cr3,

	.mmu.write_cr3		= native_write_cr3,

arch/x86/xen/xen-asm.S

+2 −0
Original line number Diff line number Diff line
@@ -102,6 +102,7 @@ SYM_FUNC_START(check_events) 
	ret

SYM_FUNC_END(check_events)



.pushsection .noinstr.text, "ax"

SYM_FUNC_START(xen_read_cr2)

	FRAME_BEGIN

	_ASM_MOV PER_CPU_VAR(xen_vcpu), %_ASM_AX
@@ -116,6 +117,7 @@ SYM_FUNC_START(xen_read_cr2_direct) 
	FRAME_END

	ret

SYM_FUNC_END(xen_read_cr2_direct);

.popsection



.macro xen_pv_trap name

SYM_CODE_START(xen_\name)